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E'Lias E. ALLEN, OE PORTLAND, MAINE.

Letters Patent No. 67,476, @ma August-e, 18er.

IMPROVEMENT IN rPISI'()I\TIAGKING.

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TO ALL WHOM IT `M/IY CONOERN:

Be it known that I, ELIAS-B. ALLEN, of Portland, in the county ofCumberland, and State of Maine, have invented an ImprovedPiston-Packing; and I hereby declare the following to be a full, clear,and exact description thereof, which will enable others to make and usemy invention, reference being had to the accompanying drawings, formingpart of this specification, in whicha is a side view broken out of thepiston; b is a top planof one form in which I contemplate thearrangement of my packing', c is a section of the'same and of a portionof the piston; d is a section of another form in whiclr I contemplatethe application of my inventionge is an edge view intended to illustratethe arrangement of the rings as they appear from the exterior; f shows asection of the piston with one form of my packing introduced therein.

The object of my invention is the production of an improvedpiston-packing, which is expanded, as is vthe case with certain others,by the steam in the cylinder as the piston is worked. I am aware of' theexistence of several patents for a similar purpose, and do not claimmetallic rings so arrangeda's to be expansible by the operation of thesteam in the cylinder. The object of my invention and claim is toembrace 'a particular arrangement of the rings in the piston, whicharrangement I will now proceed to describe.

With one form of my invention I use a. solid piston, a'portion of whichis shown at a, having a channel for the reception of the rings, as iscommon, this channel being between the two parts]l k. In the centre ofthis channel is the raised part g, leaving the two smaller groovesiz'upon either side thereof. Upon the inner edges of the partsj k isseen thc small 4groove m running entirely around tbe piston. n shows'vertical slots in the faces of the parts j k, and conducting into thesmall grooves m. There are two methods in which I contemplate theapplication of the metallic rings to form my improved packing, but theparts ofthe piston which I have above described and designated are usedin both. My invention consists furthermore of interior and outer'lcurved pieces of metal constructed and arranged as follows: What .I termthe interior pieces have the back portion o, which nearly lls the Vspacebetween the partsj and k of the piston, and rests against the raisedportion g, as clearly shown'in the gure designated d. From the centre ofthis parto projects tne shoulder p, as shown in the same ligure. Uponthis shoulder, on the upper and lower sides thereof, are placed thepieces q lr, the parts q rp, and p with its back o, loosely filling thegroove in the piston between j and k. The parts represented by q r areso arranged as to break the joints of the inner pieces designatedbyp o.This is illustrated at e and b. v To insure this a small pin is set intothe part p, as indicated atrs. The above-described arrangement of metalpacking can be used with a solid piston, inasmuch as it can be placedbetween the parts j and lc, as illustrated in tbe drawing. At c is shownan arrangement of the packing similar to that illustrated at d, withthis difference, that the shoulder p', which corresponds to the shoulderp-in the other' arrangement, has small grooves at t, and the parts g a",corresponding to q'and r in the other arrange,- ment, have small lips,which fit into the said grooves t. Unlike the arrangement illustrated atd, pressure in an outward direction, when applied within the circleformed by the'nrrangement of the' ditl'erent parts, will not force themapart, they being held together by the parts q r', breaking the jointsof the interior parts, or those designated by p o', Vand also by thefitting of the lipsorrg 1" intothe grooves on the part p". The lips on qr t somewhat loosely into the grooves in thel shoulder p in order-"toallow of a freer expansion of the packing. This form last describeddiffers from the one first described also in this, that the piston inwhich it is used must have a follower, inasmuch as the packing cannot beinserted in the channel of the solid piston shown at a.

The operation of Iny packing in both of the described forms is asfollows: When the packing is placed in its proper position in the pistonsteam is lirst taken through the. vertical slots n, thence into thesmall grooves m, thence behind the parts o or o into the space h or z',where, by its expansive force, it expands the packing to the hecessaryextent to fill the cylinder. It is 'evident that the steam is taken upononeside of the piston at the upward and upon the other at the downwardstroke, or, in other words, upon opposite sides of the small projectionsg. Disclaiming any previous arrangements of metallic piston-packing, Idesire further to specify that in upright engines, where the stroke isvertical, the partsj 7c of the piston may be ground or turned off to adepth the same as the vertical slots vin the said parts of the saidpiston shown in fig. a.

I do not claim a packing made by a -ring inserted between the ilanges ofthe head, which ring is narrower than the groove, so that as the pistonmoves the ring moves from one to the other pressed outwarrll)T by steamadmitted from the cylinder into a close chamber in or more openingsleading out therefrom and into the groove, the steam in the el Myinvention ldiffers from this, both in the construction of the outer andinner-'segments of the annular packingr in each of the two formshereinbefore specified and in the manner of admitting the steam behindthe packing to expand thev same. Furthermore, my invention diifers fromthe patent .of Nathan P. Stevens, No. 44,674, October 11, 1864, aboverecited, in the raised part g in the centre of the channel.

What I claim as my invention and desire to secure by Letters Patent, is-

1. lIn eombination with the partg of the piston, the arrangement of thesegments constructed. as illustratell at 2J o, :1nd the segments asshown at q r, in the manner and for the purposes herein described.

2. In combination with the party of the piston, the arrangement/of thesegments p o', having the channels t on the part 2f, and the segments qi", having the lips to it into /thef said channels t, in the manner andfor the purposes described. 'i

side ofthe channel, and being the piston-head through one `oseeharnberaeting as a, spring.

ELIAS B. ALLEN.

Witnesses.

WM. HENRY CLIFFORD, HENRY C. HOUSTON.

